Photoelectric Effect Flashcards

• The photoelectric effect is the emission of electrons from a metal surface when light shines on it, demonstrating the quantization of energy in electromagnetic waves.

Experimental Setup

• An experimental setup involves two electrodes connected to a galvanometer and EMF source. Light on the right-hand side plate ejects electrons, creating a photocurrent detected by the galvanometer.

Quantum Theory Predictions

• Monochromatic light consists of photons with energy E = hf or E = \frac{hc}{\lambda}. Increasing light intensity increases the number of photons, but not their energy. Electrons are ejected if photon energy exceeds the metal's binding energy.

Work Function

• The work function (\phi) is the minimum energy to remove an electron. The relationship is E = \phi + KE, considering the maximum kinetic energy (KE_max) of ejected electrons.

Experimental Verification

• Experiments confirm that increasing light intensity (above the work function) ejects more photoelectrons without changing their maximum kinetic energy. Higher photon energy increases maximum kinetic energy. Below the work function, no electrons are ejected.

Threshold Frequency and Wavelength

• The minimum energy for photon ejection occurs when KE_max = 0, where the work function equals hf0 (f0 is the threshold frequency). The threshold wavelength \lambda0 relates to the work function by: \phi = \frac{hc}{\lambda0}.